Electrolysis device

ABSTRACT

An electrolysis device ( 7 ) includes a water circuit ( 6 ), in which an electrolyzer ( 5 ), a collection container ( 1 ) and at least one pump ( 2 ) are arranged. The water is pumped by way of the at least one pump ( 2 ) out of the collection container ( 1 ) to the electrolyzer ( 5 ). The water circuit ( 6 ) is branched into at least one first branch ( 8 ) and into a second branch ( 9 ) which is parallel to the first branch ( 8 ). The electrolyzer ( 5 ) is arranged in the first branch ( 8 ) and a heat exchanger ( 3 ), for cooling the water, is arranged in the second branch ( 9 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a United States National Phase Application of International Application PCT/EP2012/076047 filed Dec. 18, 2012 and claims the benefit of priority under 35 U.S.C. §119 of European Patent Application EP 1 215 1580.3 filed Jan. 18, 2012, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to an electrolysis device with a water circuit, in which an electrolyzer, a collection container and at least one pump are arranged, wherein the water is pumped by way of at least one pump out of the collection container to the electrolyzer.

BACKGROUND OF THE INVENTION

Electrolysis devices which use an electrolyzer for the electrolytic decomposition of water into hydrogen and oxygen are known from the state of the art. In a water circuit of such an electrolysis device, thereby water from a collection container is fed to the electrolyzer by way of a pump. Then hydrogen exits out of the electrolyzer at one side and this hydrogen is led away in a targeted manner. An oxygen-water mixture exits at the other side and this is fed again to the connection container, in which a gas-water separation is then effected. All components of the electrolysis device, i.e. the collection container, the pump, a heat exchanger for heat discharge, a filter and the electrolyzer or electrolysis stack are installed in series with configurations known from the state of the art, so that a single water flow flows through all these components.

There are different types of electrolyzers; amongst others the so-called acid or proton exchange membrane electrolyzer (PEM) which comprises a proton-permeable polymer membrane and therefore can only operate with distilled water, since this would otherwise be damaged.

On operation of the electrolysis device, hereby, the pump used for feeding the water to the electrolyzer represents a limiting factor, since on account of the distilled water which is used in the circuit and which is extremely aggressive, only pumps lined with plastic instead of stainless steel can be used. These pumps, however, can only be operated with temperatures up to maximal 80° C., which is a problem due to the already above-mentioned series arrangement of the components of the electrolysis device. As already mentioned, with the known configuration the water is pumped around in the circuit. Since the applied centrifugal pumps are difficult to bleed, their position in the water circuit is usefully directly downstream of the collection container for gas-water separation, into which however the water lead away from the electrolyzer and greatly heated by this is directly introduced. Thus, this construction has the disadvantage that the temperature-sensitive pump is subjected to a very high water temperature.

Also, it is not possible to connect a heat exchanger for cooling the water heated by the electrolyzer, directly downstream of this electrolyzer, due to the high share of gas bubbles in the water which is led away from the electrolyzer. In contrast, the heat exchanger in the configurations known form the state of the art is arranged downstream of the pump, which however in turn leads to the disadvantage that the water fed to the electrolyzer is cooled by the heat exchanger, by which means the efficiency of the electrolyzer as well as its power reduces.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention, to provide an electrolysis device which at least partly avoids these disadvantages.

According to the invention, an electrolysis device with a water circuit (cycle) is provided, in which an electrolyzer, a collection container, and at least one pump are arranged, wherein the water is pumped by way of the at least one pump out of the collection container to the electrolyzer , wherein the water circuit is branched into at least one first branch and into a second branch which is parallel to the first branch, wherein the electrolyzer is arranged in the first branch and wherein a heat exchanger for cooling the water is arranged in the second branch.

The basic concept of the present invention is not to cool the water flow fed to the electrolyzer, but to let the cooling be effected in an auxiliary flow. In this manner, on the one hand the maximal temperature permissible for the operation of the pump can be utilized and on the other hand the electrolyzer can be fed with water at this temperature, which increases the efficiency. The cooling is effected in the auxiliary flow and therefore has no direct influence on the electrolysis process.

According to a preferred embodiment, the water circuit, downstream of the at least one pump branches into the at least one first branch and the second branch. This circuit arrangement has the advantage that the circulation of the water in both branches can be effected with only one pump.

Advantageously, the first branch comprises a first branch return, which runs out into the collection container.

Moreover, it is advantageous if the second branch has a second return which runs out into the collection container.

Preferably, the collection container is designed for gas-water separation.

Particularly preferably, the electrolyzer is a proton-exchange-membrane electrolyzer.

According to a further preferred embodiment, the water of the water circuit in the second branch is pumped out of the collection container to the heat exchanger by way of a further pump.

Moreover, preferably, a filter is arranged in the water circuit, in particular in the first branch upstream of the electrolyzer.

It is possible on account of the configuration of the electrolysis device according to the invention, to cool the water already before the pump, but simultaneously to supply the electrolyzer itself with water having a greater temperature or thus operating it with a higher water temperature, so that the efficiency of the installation can be improved.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

The only FIGURE is a schematic representation of a water circuit of an electrolysis device according to one embodiment of the invention is shown.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, a water circuit 6 of an electrolysis device 7 according to one embodiment of the invention is represented in the FIGURE. A collection container 1 for the gas-water separation, a pump 2, a heat exchanger 2, a filter 4 and an electrolyzer 5 for decomposing water into hydrogen and oxygen are arranged in the water circuit 6. With regard to the electrolyzer 5, it is the case of a proton-exchange-membrane electrolyzer (PEM) and as a result the water circuit 6 is operated with distilled water.

In contrast to the configurations known from the state of the art, with which the collection container 1, the pump 2, the heat exchanger 3, the filter 4 and the electrolyzer 5, as already explained, are installed in series, so that only a single water flow flows through all mentioned components, according to the invention, the water circuit 6 is branched into a first branch 8 and into a second branch 9 which is parallel to the first branch 8. The branching of the water flow pumped by the pump 2 out of the collection container 1 is thereby effected directly downstream or behind the pump 2, or upstream which is to say in front of the filter 4.

The filter 4 and the electrolyzer 5, which brings the heat into the water circuit 6, are arranged in the first branch 8. The heat exchanger 2 for cooling the water is located in the second branch 9.

A first return 10 of the first branch 8 and a second return 11 of the second branch 9 run out into the collection container 1 for gas-water separation, in which the water cooled by the heat exchanger 3 and the water heated by the electrolyzer 5 now mix. With this, a lower water temperature in the collection container 1 is achieved. This is in contrast to the configuration which is known from the state of the art and with which only the water heated by the electrolyzer 5 runs back into the collection container 1. It is possible without any problem, to use a pump which is lined with plastic, since the water in this manner is cooled already upstream of the pump 2 which pumps the water out of the collection container 1. However, simultaneously the electrolyzer 5 can also be operated at a higher operating temperature due to this configuration, and the efficiency and its performance can be increased by way of this.

According to a further embodiment which is not shown here, it is furthermore possible for the first branch 8 as well as the second branch 9 to be supplied in each case by their own pump. Moreover, according to a yet further embodiment, it is possible to divide the water circuit 6 into more than two branches.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 

1. An electrolysis device comprising: a water circuit; an electrolyzer connected to the water circuit; a collection container connected to the water circuit; a heat exchanger connected to the water circuit; and at least one pump connected to the water circuit, wherein water is pumped by way of the at least one pump out of the collection container to the electrolyzer wherein the water circuit is branched into at least one first branch and into a second branch which is parallel to the first branch, wherein the electrolyzer is arranged in the first branch and wherein the heat exchanger for cooling the water is arranged in the second branch.
 2. An electrolysis device according to claim 1, wherein the water circuit branches downstream of the at least one pump, into the at least one first branch and the second branch.
 3. An electrolysis device according to claim 1, wherein the first branch comprises a first branch return which runs out into the collection container.
 4. An electrolysis device according to claim 1, wherein the second branch comprises a second branch return which runs out into the collection container.
 5. An electrolysis device according to claim 1, wherein the collection container is designed for gas-water separation.
 6. An electrolysis device according to claim 1, wherein the electrolyzer is a proton-exchange-membrane electrolyzer.
 7. An electrolysis device according to claim 1, wherein the water of the water circuit in the second branch is pumped by way of the pump out of the collection container to the heat exchanger.
 8. An electrolysis device according to claim 1, further comprising a filter is arranged in the water circuit, in the first branch upstream of the electrolyzer.
 9. An electrolysis device according to claim 1, further comprising a further pump, wherein: water of the water circuit in the second branch is pumped by way of the further pump out of the collection container to the heat exchanger; and water of the water circuit in the first branch is pumped by way of the pump out of the collection container to the electrolyzer.
 10. An electrolysis device according to claim 2, wherein: the first branch comprises a first branch return which runs out into the collection container; and the second branch comprises a second branch return which runs out into the collection container.
 11. An electrolysis device comprising: a collection container; an electrolyzer; a collection container; a heat exchanger for cooling water; a pumping means for pumping fluid; and fluid paths cooperating with the collection container, the electrolyzer, the collection container, the heat exchanger and the pumping means to form a water circuit comprising a first branch and a second branch which is parallel to the first branch, wherein: the pumping means pumps water out of the collection container to the electrolyzer and to the heat exchanger; the electrolyzer is arranged in the first branch; the heat exchanger is arranged in the second branch.
 12. An electrolysis device according to claim 11, wherein: the pumping means comprises a pump; and the water circuit branches downstream of the pump, into the first branch and the second branch.
 13. An electrolysis device according to claim 11, wherein the fluid paths include a first path return feeding fluid into the collection container, the first path return being a part of the first branch.
 14. An electrolysis device according to claim 11, wherein the fluid paths include a second path return feeding fluid into the collection container, the second path return being a part of the second branch.
 15. An electrolysis device according to claim 11, wherein the collection container comprises a gas-water separation device.
 16. An electrolysis device according to claim 11, wherein the electrolyzer is a proton-exchange-membrane electrolyzer.
 17. An electrolysis device according to claim 11, further comprising a filter arranged in the water circuit.
 18. An electrolysis device according to claim 17, wherein the filter is arranged in the first branch upstream of the electrolyzer.
 19. An electrolysis device according to claim 11, wherein the pumping means comprises: a first branch pump arranged in the first branch of the water circuit for pumping water out of the collection container to the electrolyzer; and a second branch pump arranged in the second branch of the water circuit for pumping water out of the collection container to the to the heat exchanger.
 20. An electrolysis device according to claim 12, wherein the fluid paths comprise: a first branch return feeding fluid into the collection container; and a second branch return feeding fluid into the collection container. 